I didn't know that the author of that godawful trainwreck even had another series.
I was curious to see if he could actually write something good, so I looked it up, then tracked it down and read the first dozen chapters or so, and I'd say the answer is no.
Well - it is better than Rent a Girlfriend, but only insofar as it couldn't possibly be worse.
The basic setup is seven siblings - two boys and five girls (five girls - where have I seen that before?) - who are suddenly told by their fabulously wealthy and conveniently absent father that they're not actually blood related.
The mc is the eldest son, who's actually the middle child. The other son is virtually non-existent, which is necessary because he actually knows how to talk to girls and actually does it, so if he was interacting with the sisters at all, the story would instantly turn into NTR, since the mc is predictably pathetic and the bulk of every chapter, just like Rent a Girlfriend, is his endlessly droning thought stream of insecurity, confusion, doubting and second-guessing. He's marginally better than Kazuya, but that's not really an accomplishment.
The girls are decidedly better than any of the ones in RaG, but again - they couldn't hardly be worse. They're really just animated tropes though - the teasingly provocative oldest sister, the emotionlessly provocative meganekko, the twin-tailed tsundere, the cute sporty girl and the painfully shy but secretly aggressive youngest.
And... that seems to be about it.
When I got bored with it, I skipped forward to the latest chapter (27), which is one of the sisters basically overtly confessing to him then kissing him, believing that he's asleep, which of course then leads to him revealing, after she leaves, that he's been awake the whole time. And what does he do? He shout/thinks to himself, "What the hell was that?!"
It's probably safe to assume that if this goes 300 chapters, that's what he'll still be doing.